Electrically driven fans have been utilized extensively virtually since the invention of the electric motor itself. There are a large variety of types including radial flow fans, axial flow fans, centrifugal fans and the like. Each type of fan has various subtypes.
For example, axial flow fans may be generally categorized as being either ducted or unducted. An example of an unducted, axial flow fan is a common household cooling fan.
Ducted axial flow fans are provided with some sort of duct or housing that fits about the impeller closely adjacent the tips thereof so as to confine the air flow. Not untypically, in order to avoid complex gearing or the like, the impellers are mounted directly on the rotor shaft of an electrical motor in such ducted constructions which in turn means that the electric motor must be at least aligned with or even located internally of the ducting. Mounting of the motor may then become a problem as may the cooling thereof. The present invention is directed to overcoming one or more of the above problems.